Systems and methods for treating a hollow anatomical structure

ABSTRACT

A catheter includes multiple primary leads to deliver energy for ligating a hollow anatomical structure. Each of the primary leads includes a resistive element located at the working end of the catheter. Separation is maintained between the leads such that each lead can individually receive power. The catheter can include a lumen to accommodate a guide wire or to allow fluid delivery. Energy is applied until the diameter of the hollow anatomical structure is reduced to the point where occlusion is achieved. In one embodiment, a balloon is inflated to place the resistive elements into apposition with a hollow anatomical structure and to occlude the structure before the application of energy. The inflated balloon impairs blood flow and facilitates the infusion of saline, or medication, to the hollow anatomical structure in order to reduce the occurrence of coagulation and to improve the heating of the structure by the catheter.

RELATED APPLICATIONS

This application is a continuation of copending U.S. application Ser.No. 13/300,725, filed on Nov. 21, 2011, entitled “SYSTEMS AND METHODSFOR TREATING A HOLLOW ANATOMICAL STRUCTURE,” which is a continuation ofU.S. application Ser. No. 13/151,950, filed on Jun. 2, 2011, nowabandoned, entitled “SYSTEMS AND METHODS FOR TREATING A HOLLOWANATOMICAL STRUCTURE,” which is a continuation of U.S. application Ser.No. 12/206,649, filed on Sep. 8, 2008, now U.S. Pat. No. 7,955,369,entitled “SYSTEMS AND METHODS FOR TREATING A HOLLOW ANATOMICALSTRUCTURE,” which is a continuation of U.S. application Ser. No.11/236,316 filed on Sep. 27, 2005, now abandoned, entitled “SYSTEMS ANDMETHODS FOR TREATING A HOLLOW ANATOMICAL STRUCTURE,” which claims thebenefit of priority under 35 U.S.C. §119(e) of U.S. ProvisionalApplication Nos. 60/613,415, filed on Sep. 27, 2004, entitled “RESISTIVEELEMENT SYSTEM,” and 60/701,303, filed on Jul. 21, 2005, entitled“RESISTIVE ELEMENT SYSTEM,” all of which are hereby incorporated byreference in their entirety and are to be considered a part of thisspecification.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates generally to a method and apparatus for applyingenergy to constrict and/or shrink a hollow anatomical structure such asa vein, and more particularly, a method and apparatus to conductelectrical current and/or heat to the wall of the hollow anatomicalstructure.

SUMMARY OF THE INVENTION

In one embodiment, a catheter comprises an elongate shaft and aresistive heating element located near the distal end of the elongateshaft. A temperature-sensing element is located in proximity to theresistive heating element, and may be centered along the length of theheating element, or offset from center. The resistive heating elementmay comprise a coil, and the coil may be of a constant pitch or of avarying pitch.

In one embodiment, a catheter comprises an elongate shaft and aresistive heating element located near the distal end of the elongateshaft. A sheath is slidably disposed on the shaft. The sheath andcatheter are relatively moveable between a first configuration in whichthe sheath covers substantially all of the resistive heating element,and a second configuration in which the sheath covers less thansubstantially all of the resistive heating element. The resistiveheating element may comprise a coil, and the coil may be of a constantpitch or of a varying pitch.

In another embodiment, a catheter system comprises an elongate shaft andan energy-emission element located near the distal end of the elongateshaft. The energy-emission element optionally includes a plurality ofemission segments, and each of the segments is independently operable toemit energy into the surroundings of the energy-emission element.Optionally, the catheter system further comprises a power sourcedrivingly connected to the emission segments. The power source isoperable pursuant to a multiplexing algorithm to deliver power to, andoperate, the emission segments in a multiplexed fashion. In oneembodiment, the energy-emission element comprises a resistive elementsuch as a resistive coil. In another embodiment, the energy-emissionelement comprises an RF emitter.

In another embodiment, a catheter system comprises an elongate shaft andan energy-emission element located distal of the elongate shaft. Theenergy-emission element has an effective axial length along which theenergy-emission element emits energy. The effective axial length isadjustable.

In another embodiment, a catheter comprises an elongate shaft and anexpandable shaft located on a distal portion of the elongate shaft. Anumber of heater elements are expandable by a balloon. The heaterelements may have a wavy, sinusoidal or serpentine configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an overall view of a resistive element systemaccording to one embodiment;

FIG. 2 illustrates an exemplary embodiment of a catheter sheath in apartially retracted position usable with the resistive element system ofFIG. 1;

FIG. 3 illustrates a closer view of an exemplary embodiment of acatheter usable with the resistive element system of FIG. 1;

FIG. 4 illustrates a cross-sectional side view of a working end of thecatheter of FIG. 3;

FIG. 5 illustrates a side view of another embodiment of the working endof the catheter of FIG. 3;

FIG. 6 illustrates a side view of yet another embodiment of the workingend of the catheter of FIG. 3;

FIG. 7 illustrates a side view of yet another embodiment of the workingend of the catheter of FIG. 3;

FIG. 7A is a table depicting an exemplary treatment cycle usable withthe catheter of FIG. 7;

FIG. 7B illustrates two views of an embodiment of a catheterincorporating external fluid grooves and an external coil electrode;

FIG. 7C illustrates an embodiment of a resistive element system havingmultiple protruding resistive elements;

FIG. 7D illustrates a side view of a resistive element system includingan expandable balloon and a set of fluid ports, according to oneembodiment of the invention;

FIG. 8 illustrates another embodiment of an expandable device having anexpandable electrode;

FIG. 9 illustrates yet another embodiment of an expandable device havingan expandable braid electrode;

FIG. 10 illustrates another embodiment of a working portion of thecatheter body with individually expandable loops;

FIG. 10A-10C illustrate other embodiments of a working portion of thecatheter body;

FIG. 11 illustrates an exemplary embodiment of an expandable set ofspline electrodes capable of conforming and contacting a vein wall;

FIG. 12A illustrates an embodiment of the working portion of a catheterhaving a conformable helical electrode axially coiled on a shaft;

FIG. 12B illustrates the device of FIG. 12A being radially expanded byrotation of a distal catheter portion;

FIG. 12C illustrates the device of FIG. 12B expanded and compresseddistally to remove inter coil gaps;

FIG. 13A illustrates an exemplary embodiment of a strip electrode coiledsubstantially normal to the catheter shaft axis; and

FIG. 13B illustrates an exemplary embodiment of the device of FIG. 13Ahaving multiple strip electrodes laid flat by uncoiling the device.

FIG. 14 illustrates an exemplary embodiment of an indexing HAS treatmentsystem.

FIG. 14A illustrates a side view of a heating element of the system ofFIG. 14 having a portion of a resistive wire removed.

FIG. 15 illustrates an exemplary embodiment of a catheter useable withan embodiment of an indexing HAS treatment system.

FIG. 16, which includes FIGS. 16A-16D, illustrates another exemplaryembodiment of a catheter useable with an embodiment of an indexing HAStreatment system.

FIGS. 17 and 18 illustrate exemplary embodiments of markings usable forvisual verification of indexing positions.

FIGS. 19 and 20 illustrate exemplary embodiments of a movable datumdevice.

FIG. 21, which includes FIGS. 21A-21D, illustrates another exemplaryembodiment of an indexing system.

FIGS. 22A-22C illustrate other exemplary embodiments of markings and/orsystems usable for visual verification of indexing positions.

FIGS. 23A and 23B illustrate an embodiment of the invention usingprinted markers arranged in a repeatable pattern.

FIG. 24, which includes FIGS. 24A-24D, illustrates another exemplaryembodiment of an indexing system.

FIGS. 25A and 25B illustrate other exemplary embodiments of an indexingsystem.

FIG. 26 illustrates an exemplary embodiment of an indexing system havinga temperature sensor.

FIG. 27 illustrates an exemplary embodiment of an indexing system havingmultiple temperature sensors.

FIGS. 28A-28C and FIGS. 29A-29B illustrate exemplary embodiments ofindexing systems for facilitating automatic movement of a catheter.

FIG. 30, FIGS. 31A-31B, and FIGS. 32A and 32B illustrate exemplaryembodiments of linkages usable to index a catheter by a certain amount.

FIGS. 33A-33B and FIGS. 34A-34B illustrate exemplary embodiments of anindexing system having a switch to control power applied duringtreatment.

FIG. 35 illustrates a screen shot of an exemplary embodiment of acontrol system usable with an indexing system, according to oneembodiment of the invention.

FIG. 36 illustrates a flowchart of the control system and indicatessteps taken during treatment, according to one embodiment of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The features of the system and method will now be described withreference to the drawings summarized above. The drawings, associateddescriptions, and specific implementation are provided to illustrateembodiments of the invention and not to limit the scope of theinvention.

In addition, methods and functions described herein are not limited toany particular sequence, and the acts or states relating thereto can beperformed in other sequences that are appropriate. For example,described acts or states may be performed in an order other than thatspecifically disclosed, or multiple acts or states may be combined in asingle act or state.

FIG. 1 illustrates an embodiment of a resistive element system forapplying energy to the wall of a hollow anatomical structure such as(but not limited to) the inner wall(s) of a vein, e.g. a greatersaphenous vein or a varicose vein. As illustrated, the resistive elementsystem comprises a catheter 1. The catheter 1 includes a catheter shaft3, which may be used to maneuver the distal portion 4 of the catheter 1during placement. In one embodiment, the catheter shaft 3 is comprisedof a biocompatible material having a low coefficient of friction. Forexample, the shaft 3 may comprise a polyimide. In other embodiments, theshaft 3 may comprise PEEK, TEFLON®, HYTREL®, or any other such suitablematerial. In one embodiment, the catheter shaft 3 is sized to fit withina vascular structure that may be between 2 and 14 French, but preferablybetween 4 and 8 French, which corresponds to a diameter of between 1.3mm (0.05 in) and 2.7 mm (0.10 in), or other sizes as appropriate. Thedistal portion 4 transfers energy (e.g. heat) directly to an inner veinwall. The proximal end of the catheter has a handle 5. The handle 5includes a port for fluid and a connection 6 for interfacing with anenergy source 2.

In one embodiment, an energy source 2 comprises an alternating current(AC) source, such as an RF generator. In other embodiments, the energysource 2 comprises a direct current (DC) power supply, such as, forexample, a battery, a capacitor, or other energy source. The powersource 2 may also incorporate a controller that, by use of amicroprocessor, applies power using a temperature sensor (e.g. athermocouple or a resistance temperature device) located in the workingportion of the catheter 1. For example, the controller may heat thetissue of a hollow anatomical structure to a set temperature. In analternate embodiment, the user selects a constant power output of theenergy source 2. For example, the user may manually adjust the poweroutput relative to the temperature display from the temperature sensorin the working portion of the catheter 1.

FIG. 2 illustrates another embodiment of the resistive element system.As shown, the catheter includes an outer retractable sheath 12. Thesheath 12 is advantageously used to protect the device during placement,facilitate introduction of the device, and/or adjust the exposed axiallength of the resistive element for a user-selected and variabletreatment length. For example, the sheath 12 may be used (e.g., pulledback (proximally) or pushed forward (distally)) to adjust the length ofthe heated region of the catheter that is exposed to a wall of thehollow anatomical structure.

FIG. 3 illustrates the catheter 1 with a section A-A, which is furtherdepicted in FIG. 4. In particular, FIG. 4 illustrates a detailed crosssectional portion of the resistive element and internal components ofthe catheter 1. As will be appreciated, the distance between theillustrated adjacent coils 8 may be of consistent or varied spacing.

The distal section 4 in FIG. 4 shows the resistive element 8 covered bya sleeve 7. In one embodiment, the sleeve 7 is a thin-walled tube from0.00025″ to 0.003″ thick. In other embodiments, sleeve may have a wallthickness of less than 0.00025″ or of more than 0.003″. In oneembodiment, the sleeve 7 comprises PET (polyethylene terephthalate). Inother embodiments, the sleeve 7 may comprise TEFLON®, polyimide or otherthin walled sleeve material which remains substantially stable for thedesired temperature range. The material selection process of sleeve 7may be determined by polymers with nonconductive or electricallyinsulative properties.

FIG. 4 also shows an internal lumen 10 of the catheter, whichcommunicates through an open lumen from the distal tip to the proximalhandle. In one embodiment, the lumen 10 is used for delivery of fluids,such as for example, saline, a venoconstrictor, sclerosant,high-impedance fluid, physiologic tissue adhesive, hydrogel, or thelike. In addition, upon completion of treatment, a hydrogel may beexuded from the distal catheter end allowing for complete vesselocclusion. For example, the hydrogel may be biocompatible orbioresorbable. In other embodiments, the hydrogel may be displaced bythe constriction of the hollow anatomical structure resulting from thethermal injury response which results in substantially completeocclusion. In those sections of the hollow anatomical structure in whichthe material has not completely compressed, it can be resorbed by thebody naturally. In yet other embodiments, the lumen 10 may alsoaccommodate a guide wire for catheter placement.

In one embodiment, the resistive element 8 is made of resistive wirethat generates heat when the energy source is connected and applied tothe catheter. As shown in FIG. 4, the resistive wire comprises a roundcross-section. In other embodiments, the resistive wire mayalternatively be rectangular, ovular, or another geometricalcross-section. Preferably, the relative resistance or impedance of theresistive element 8 is designed to correlate to the energy source. Forexample, the resistance of resistive element 8 may be determined by awire gage that relates to the catheter diameter, the energy required,and the energy source requirements. The wire may comprise a wide varietyof conductive materials, such as, for example, nickel chromium, copper,stainless steel, NITINOL®, ALUMEL®, and the like.

The resistive element 8 illustrated in FIG. 4 is a closed wind coil(i.e., with substantially no inter-coil spacing). In one embodiment, anelectrical connection, such as soldering at the proximal end and/or thedistal end of the coil, couples the resistive element 8 to a signal wire9. As shown in FIG. 4, the signal wire 9 is a distal return signal wire.For example, the signal wire 9 may run the internal length of thecatheter 1 to a connector cable 6. In one embodiment, the signal wire 9extends from the proximal end of the coil. In such an embodiment, thesignal wire 9 is a larger gage copper wire (e.g., 28 to 34 gage) inorder to reduce possible heating within the main body of the catheter 1.

In one embodiment, the resistive element 8 comprises a constant,closed-pitch coil. Alternatively, the resistive element may have avarying pitch and/or a varying inter-coil spacing. For example, avarying coil pitch and/or spacing may be advantageously used to vary theheat output over the axial length of the heating element. An axially(and/or radially) varying heat output from the resistive element isuseful in providing a substantially uniform tissue and/or devicetemperature during treatment. For example, such a variation in coilpitch may be advantageous in situations involving fluid flow within thehollow anatomical structure. In such cases, the fluid tends to absorbheat output from the proximal portion of the resistive element to agreater degree than heat output from the distal portion. This can resultin a reduction of the heat actually applied to the wall of the hollowanatomical structure adjacent to the proximal portion of the resistiveelement relative to the central and distal sections. As the fluid flowspast the proximal section of the heating element, the fluid itself willbe heated. The heated fluid then flows across the middle and distalsections of the resistive element 8, thereby increasing the temperatureof treatment for these sections. One embodiment, intended to counteractthis effect, comprises a close-pitch wind of the heating element in theproximal portion (implying a higher heat output in the proximal portion)while the middle and distal sections may have a comparatively moreopen-pitch wind (i.e., the inter-coil spacing increases in the distaldirection). This configuration decreases the heat output along portionsof the coil in order to compensate for the added heat from the proximaladjacent sections. That is, the variable coil pitch may be used tocorrect for higher temperatures of the middle sections of the resistiveelement in comparison with lower temperatures of the end sections of theresistive element. A thermally-insulating material (such a naturalrubber, silicone, or an elastomer) may be used to shield the internallumen from heating, or to selectively reduce external heat transfer fromthe resistive element.

In another embodiment, portions of the resistive element having aclose-pitch wind are used to heat larger portions of an anatomicalstructure (e.g., portions having a larger diameter) while portions ofthe resistive element having an increased coil spacing are used to heatsmaller portions of the anatomical structure (e.g., portions having asmaller diameter).

In other embodiments, the coil wind comprises more than one radiallydisplaced layer. For example, as shown in FIG. 5, the successive layers14 and 15 of winds may be counter-wound to overlap and can also have avariable pitch over the axial length of the shaft. This configurationmay be used to provide a greater heating density, or to provide moreuniform heating if the coil winds are spaced to increase the length ofheating segment with a limited length of coil wire.

In one embodiment, the resistive element 8 comprises a bifilar wirecoil, which is advantageous in processing as it can be wound as a singlefilament. A bifilar wire also maintains a constant distance between thetwo embedded wires, which can help to maintain accurate overall spacingin order to provide uniform heat distribution. In some embodiments, thewind of the bifilar wire coil may comprise a variable pitch, asdiscussed previously. The bifilar wire coil may also combine wireconnections (i.e., connections between the multiple wires in the wirecoil) at one end of the catheter, preferably the proximal end. Forexample, the distal end may comprise an electrical connection betweenthe two wire ends in order to create a continuous loop. In alternativeembodiments, the bifilar wire can comprise more than 2 wires.

FIG. 6 shows the bifilar wire 16 coupled through solder joints 17 tosignal wires 18 and 19. In one embodiment, the joints 17 are spot weldedor bonded with a conductive epoxy. In addition, the signal wires 18 and19 may extend internally through the catheter shaft to the connector 6located at the proximal end (e.g. see FIG. 1). As previously discussed,FIG. 6 shows one example of a variable wind configuration.

In other embodiments of the invention, energy is applied separately toeach wire of the bifilar wire coil. For example, applying energyseparately to each wire may be used to vary and control the power andheat transferred from the device to the vessel. In one embodiment, asingle coil is used for smaller hollow anatomical structures, while bothcoils are used with larger hollow anatomical structures.

FIG. 2 shows a single sensor as part of the resistive element. In otherembodiments, multiple sensors are placed along the axial resistiveelement length. For example, the energy source may advantageouslymonitor the individual sensors and use the multiple inputs fortemperature feedback. In another embodiment, the controller may monitorfor high temperature or low temperature signals. For example, analgorithmic process may be used to control the current applied to thevarious wire coils, thus maintaining a substantially axially-uniformtemperature and/or heat output.

In another embodiment, the resistive element 8 comprises multiple coils,which are sequentially placed axially on the catheter shaft representedby the resistive elements 21 through 28, as shown in FIG. 7. Forexample, each resistive element may be individually temperaturecontrolled and/or may comprise a temperature sensor.

Alternatively the sequential resistive elements may be used in a powercontrol mode that relies on manual energy control.

Alternatively, in one embodiment of the invention having multipleresistive elements, a temperature sensor is located on the most distalresistive element. For example, the most distal resistive element may beused for the initial treatment and the successive coil electrodes mayuse the same and/or a predetermined energy-time profile.

In one embodiment, a method of use of the resistive element systemincludes multiplexing through each of the resistive elements 21-28 shownin FIG. 7A. The term “multiplex” as used herein is a broad term and isused in its ordinary sense and includes without limitation theenergizing, or heating, of at least one resistive element for a specificdwell time and cascading, or moving, to another resistive element untilthe end resistive element is reached or until a cycle is completed. Thecycle is then repeated until the complete treatment time is reached.

FIG. 7A shows an example using the resistive element configuration shownin FIG. 7. In one embodiment, the resistive elements 21 through 28 aresequentially energized for a dwell time of approximately 0.2 seconds. Inthe example shown, three resistive elements are powered at a time. Thetable has shaded blocks of time, which represent the time that energy isbeing delivered to the specified resistive elements. Since threeresistive elements are on at one time and the dwell time is 0.2 seconds,each resistive element is on for a total of 0.6 seconds during onecycle. In the table, for time 0 to time 0.2 seconds, resistive elements21, 22 and 23 are energized. For time 0.2 seconds to 0.4 secondsresistive elements 22, 23 and 24 are energized. This process repeats bystepping through the resistive element set. For the 8 resistive elementsshown, one complete cycle takes 1.6 seconds. In one embodiment, to avoidovercooling of a particular resistive element, the cycle time is of ashort duration and/or the total number of resistive elements is limited.That is, in one embodiment, a resistive element may be re-energizedbefore substantial cooling takes place. In addition, in one embodiment,to increase the treatment zone, the catheter may comprise multipletreatment zones, such as for example, groups of eight resistiveelements, as is shown in FIG. 7. Each group of eight resistive elementsmay treat the wall of the hollow anatomical structure before energy isapplied to the next group of resistive elements. Alternative modes ofmultiplexing may also be employed. For example, the number of adjacentresistive elements simultaneously energized may vary. Also, the entirecycle may re-start at the first end energized, or the last endenergized. Another mode of multiplexing may be accomplished through asensing of the tissue impedance. Once a certain level is achieved, thenext set of resistive elements is then energized.

Alternatively, at least one of the eight resistive elements is energizedto treat the hollow anatomical structure until treatment is complete.Then, the next resistive element(s) apply a similar treatment time, andso on moving along the treatment zone. For the eight resistive elementsillustrated in FIG. 7, the treatment may be for one cycle. For example,resistive element 21 may treat the hollow anatomical structure forapproximately 20 seconds. Once resistive element 21 has completedtreatment, resistive element 22 repeats the same treatment time andenergy settings. Such a process may continue for resistive elements 23through 28.

In other embodiments of the invention, alternate treatment cycles may beused. For example, resistive elements 21 and 22 may concurrently treatthe hollow anatomical structure for approximately 20 seconds. Thenresistive elements 23 and 24 apply a similar treatment, and so forththrough resistive elements 27 and 28 to complete the cycle.

FIG. 7B illustrates another embodiment of an electrically resistiveheating element having an open pitch wind, but omitting an outer sleeve7. FIG. 7B shows the coil spacing greatly exaggerated in order to seethe tube detail 44. In one embodiment, the inter-coil spacing isselected to create a path for fluids. For example, the inner lumen 45(which is shown as a single lumen, but may include multiple lumens) ofthe catheter may deliver fluid to the vessel by the additional pathways46 which are external surface features and radial holes (intermittentlyspaced along the grooves) in the tube wall. The fluid may be a saline, avenoconstrictor, or the like. In one embodiment of a method of using thedevice of FIG. 7B, the device is placed in the hollow anatomicalstructure. The hollow anatomical structure is then treated with thevenoconstrictor via the catheter lumen 45 and 46. Then the hollowanatomical structure is treated by heating the constricted wall of thehollow anatomical structure.

FIG. 7C illustrates an embodiment of a resistive heating elementcomprising multiple resistive elements with separate and distinctprotruding resistive elements made of resistive materials, such as, forexample, KANTHANAL®, NICHROME®, CHROMEL®, ALUMEL®, KOVAR®, Alloy 52,TITANIUM, ZIRCONIUM, combinations of the same or the like. In oneembodiment, a series of resistive elements are spaced axially along thecatheter shaft; each of these resistive elements comprises adoubly-truncated-spherical body 52. In one embodiment, each resistiveelement may be attached to a signal wire by solder, spot weld, or othermethod. For example, the signal wire may run internal to the cathetertube and attach to the cable and connector 6.

FIG. 7D is another embodiment of the working portion of the catheter.The device shown has the addition of a balloon 47, expanded by ports 49.As shown, the balloon 47 is located proximate to the resistive element.The balloon 47 may be used to occlude or substantially occlude a hollowanatomical structure. Additional fluid ports 50 proximal to theresistive element 48 are for fluid placement within the hollowanatomical structure.

In one embodiment, the catheter is placed in the hollow anatomicalstructure, and then the balloon 47 is inflated through the ports 49.Once the balloon is inflated, the fluid ports 50 clear the hollowanatomical structure of native fluid, such as blood, distal to theballoon 47, by injecting a displacing fluid, such as, for example,saline. In one embodiment, the displacing fluid is followed by anotherinjection of a venoconstrictor, which reduces the hollow anatomicalstructure lumen size prior to treatment. By temporary reduction of thehollow anatomical structures size, the treatment time used for theresistive element 48 is reduced, thereby resulting in a more effectiveand safe treatment.

Expandable Resistive Element Devices:

Serpentine:

Another embodiment is shown in FIG. 8, which incorporates an expandableresistive element 32 on a balloon 31. In one embodiment, the balloon 31is made of a biocompatible material such as, but not limited tosilicone, PET, urethane, latex, C-FLEX®, combinations of the same or thelike. The balloon 31 is attached to the catheter shaft 30 at the workingend of the catheter. Both ends of the balloon are sealed on the shaftand are fluid tight. The catheter shaft section within the ballooncontains fluid ports (not shown). The ports are connected to internalopen lumen(s) which run internally to the shaft to the proximal end. Thelumen(s) at the proximal end at the handle 5 are connected to luercomponents for external fluid connections. These are used to expand andcollapse the balloon.

The resistive element 32 is a serpentine component, which is placedcircumferentially around the exterior of the balloon 31 and cathetershaft. In one embodiment, the serpentine component expandscircumferentially as the silicone balloon expands. In one embodiment,the serpentine component 32 is made of NITINOL®. For example, the shapememory aspect of NITINOL® may be advantageously utilized to help thecomponent remember its expanded or collapsed position. In otherembodiments, other nickel based spring alloys, other spring alloys, 17-7stainless steel, Carpenter 455 type stainless steel, beryllium copper,or other similar materials may also be used.

In an alternate embodiment, the serpentine component 32, is locatedwithin the wall of the balloon material or between two layers of thesilicone balloon material. This embodiment results in the serpentineresistive element being more integral to the assembly.

A temperature sensor 33 is attached to the serpentine component fortemperature control during application of the energy. In FIG. 8 thesensor is attached near the proximal end of the serpentine, but may beattached at any point axially. In one embodiment, the attachment of thesensor is accomplished by soldering, bonding or essentially tying itonto the section of the serpentine wire. The ends of the serpentinecomponent 35 are attached to signal wires, which run through thecatheter internal open lumen and are connected to the connector cable 6.These signal wires may be attached by solder (or previously discussedmethods) to the serpentine component.

This embodiment of FIG. 8 places the resistive element in apposition tothe wall of the hollow anatomical structure prior to treatment by use ofthe expanding balloon 31. Thus, one device may be adjusted to fitmultiple sizes of hollow anatomical structures. The balloon 31 andserpentine component may also collapse during the last portion of thetreatment or as the treatment is completed. The intent of collapsing thedevice during the last portion of treatment is to maintain appositionwith the walls of the hollow anatomical structure while allowing thetissue to shrink and/or constrict in order to occlude.

For improved viewing of the balloon during expansion, a contrast mediummay be used for fluoroscopy or an ultrasonic contrast. For example,micro bubbles may be employed as part of the balloon fluid forexpansion. This can be applicable to any expandable resistive elementusing a fluid filled balloon.

In one embodiment, the balloon is capable of displacing a substance,such as blood, from a treatment area. In another embodiment, the balloonis further capable of directing heat toward the wall of an anatomicalstructure by bringing at least a portion of the resistive element inproximity with, or in contact with, the wall. In yet other embodiments,the balloon is configured to collapse in response to the collapsing ornarrowing of the anatomical structure and/or is configured to collapsemanually.

In one embodiment, an indicator in the handle of the resistive elementsystem shows the state of inflation of the balloon. For example, theindicator may comprise a substance or display that moves axially to showdeflation of a balloon. For instance, the indicator may be coupled tothe expandable member (e.g., the balloon), such that expansion of theexpandable member causes corresponding changes (e.g., movement) of theindicator. In other embodiments, the out-flowing saline is employed in apressure or level-gauge like configuration (e.g., a thermometer-likeconfiguration) to indicate the state of inflation of the balloon.

Expandable Braid:

FIG. 9 illustrates another embodiment of an expandable resistive heatingelement. This embodiment utilizes a metal braid wire 36 as the workingresistive element. In one embodiment, the wire is round and made ofNITINOL®. However, in other embodiments, the braid wire may be flat wireand/or comprise another spring-type or shape memory material asdiscussed above. For the device, the elastic characteristics of NITINOL®are beneficial to the method of expanding and collapsing the device. Inone embodiment, the braid is heat set in the nearly fully expandedposition. In other embodiments, the balloon is used to expand the braid.

In one embodiment, the braid wire is sleeved in polyimide to isolate thewires from each other where they overlap. In other embodiments, othermaterials may be used, such as for example, TEFLON®, urethane, and thelike. The braid component may be created using standard braidingtechnology. Alternatively, a single wire may be woven into the braidcomponent. The method is relevant for the overall resistance orimpedance of the device for the energy source.

The proximal and distal ends of the braid 36 component are captured in atwo-part crimp sleeve, 39 and 41, in order to anchor the ends to thecatheter tube, 40 and 37. The braid 36 in this embodiment is expanded bythe use of the catheter stylet 37, which runs the internal axial lengthof the catheter, from the distal tip 41 to the proximal handle 5. Theproximal end of the stylet passes through a Touhy Borst type fitting onthe catheter handle 5 and in turn is a handle for stylet manipulation.In this case, pushing the stylet 37 distally collapses the braid(illustrated in the upper figure of FIG. 9), while pulling the stylet 37expands the braid (illustrated in the lower figure of FIG. 9).

In the embodiment of the invention illustrated in FIG. 9, a balloon 38is placed internal to the braid 36 such that the ends are distal to thecrimp section 39 and proximal to the crimp 41. As previously discussed,the balloon 38 is silicone, but it can be of other materials previouslyidentified. This balloon then uses internal lumen and side port (notshown) of the catheter stylet 37 for inflation and deflation.

It should be noted that the typical silicone extrusion may expandaxially and radially when inflated. This causes the balloon to become“S” shaped for a set axial length of tubing, thus causing the braid tohave non-uniform tissue apposition with the hollow anatomical structure.To compensate for this issue, the extrusion 38 may be pre stretchedaxially just prior to anchoring on the catheter tubing to the styletcomponent 37. The stretched tube may then expand radially with little tono axial expansion, depending on the amount of pre-stretch done. Theballoon may be used to occlude the vessel to impair blood flow and toremove blood from the braid portion of the catheter. This creates astatic fluid volume and makes the heat treatment more efficient. Also,the balloon promotes braid apposition with the hollow anatomicalstructure. In other embodiments, the balloon is at least partiallyexpanded and contracted through expansion and compression of the ends51, 54.

In one embodiment, a temperature sensor 42 is attached to the braid wirealong its axial length. The sensor 42 may be used for temperaturecontrol during the application of energy for the controller. Althoughthe sensor 42 is shown attached near the proximal end of the braid wire,the sensor 42 may be located along other portions of the braid wire. Inaddition, more than one sensor may be used.

In another embodiment, the balloon is a separate device from the braiddevice. For example, the balloon device may fit within the lumen of thebraid device, and the tips of both devices may connect and anchor to oneanother. For example, the anchor mechanism may include a set of male andfemale threads appropriately sized. Alternatively the device tips may beanchored together by use of axially aligned holes in both tips, throughwhich a wire is placed and tied off. Alternatively, the tips may bedesigned with a spring ball detent to anchor the tips together.Alternatively, strong magnets of opposite polarity may be used to locatethe tips and hold them together.

Expandable Loop:

Another embodiment, shown in FIG. 10, utilizes at least one expandableloop, which emanates from the side of the main catheter body. One end ofthe loop 55 is anchored to the catheter shaft 53. The other end of theloop passes through an opening 56 in the sidewall of the catheter tube53 and runs through the catheter lumen to the handle 5 at the proximalend. This end of the loop acts like a stylet, in order to manipulate theloop shape and size. In one embodiment, the wire coils around the maincatheter body with spaced attachment points (such as by entering intoand exiting from segments of a lumen within the main catheter body) suchthat by advancing the wire the coils extend beyond the main catheterbody in the fashion of circular coils tending toward a right angle tothe axis of the main catheter body. The wire is typically circular incross section. In one embodiment, the loop is pre-shaped in order toextend outward toward the walls of the hollow anatomical structure andeventually into contact with them. Alternatively the wire section thatforms the actual exposed loop portion 54 may be a flat wire,rectangular, ovular, or other geometrical cross section. In oneembodiment, rotating the stylet handle end of the loop manipulates, ortwists, the loop toward or away from the catheter shaft.

The loop 54 may comprise a resistive element similar to the element 4 ofFIG. 1. For example the loop 54 may comprise a resistive element coil 57wrapped around it. In addition, each loop may have a temperature sensoron the resistive element 57 for use in temperature controlled energydelivery. In other embodiments, each resistive element is covered with asleeve. For example, the sleeve material may comprise PET, TEFLON®,polyimide, or other material.

Wavy Expandable Length:

Another embodiment is shown in FIG. 10A and utilizes at least oneexpandable formed set of bends. A main spline 73 shown in FIG. 10C makesthe backbone and is made of NITINOL®. In other embodiments, the spline73 is made of other nickel-based spring alloys, 17-7 stainless-steel,Carpenter 455 type stainless-steel, or beryllium copper, or othersimilar materials. An embodiment illustrating details of the spline 73is shown in FIG. 10C. The illustrated spline 75 is wound with aresistive wire 76 as previously discussed in detail with respect to FIG.4. The device illustrated in FIG. 10A may also include a temperaturesensor. Because the illustrated spline 73 slides into the tube 70, ithas an outer sleeve 77 made of TEFLON® for reduced frictional force.

In one embodiment, the spline 73 is straightened by withdrawing itproximally into the tube 70. For example, the tube 70 may comprise aninner liner 72, which extends out of the tube end and is formed into anouter lip 71. In addition, FIG. 10A-10C show the spline 73 as2-dimensional. However, a skilled artisan will recognize from thedisclosure herein that the spline 73 may also comprise various3-dimensional shapes, such as for example, a helical wind. This shapemay be used to improve contact of the heating element to the wall of thehollow anatomical structure during the treatment cycle.

Expandable Floating Ribbon:

FIG. 11 illustrates another embodiment using at least one expandableresistive element. The pre-shaped splines 52, 6 splines in this figure,act as individual resistive heating elements. The set of splines 52 areattached radially about the catheter shaft 51. The expandable resistiveelement set has at least one expanded section. In FIG. 11, the deviceshown has 2 expandable sections. The resistive element set is anchoredat the mid point 53, which does not substantially expand. The tip 54 andproximal end attached to the shaft 51 also do not substantially expand.

The device is designed to collapse by use of an outer sheath, which inFIG. 11 is in a retracted position. For example, the sheath may be usedto help place the device in the vessel and to help remove the deviceafter treatment. One intent of the self-adjusting splines is to let themexpand so they will be in apposition to the tissue and adjust to anyaxial bends or curves in the hollow anatomical structure. As the hollowanatomical structure is heated during treatment, the lumen of thestructure constricts and/or shrinks and the spline set adjusts andcollapses concurrently with the lumen. This same characteristic alsogives the device of FIG. 11 versatility, as it is able to accommodatevarying sizes of hollow anatomical structures.

Alternatively, the device comprises a stylet wire similar to the braiddevice of FIG. 9 in order to collapse and expand the pre-shaped splines.In this embodiment, the splines may be manually collapsed duringtreatment in order to follow the occlusion of the hollow anatomicalstructure.

Each spline 52 is made of a resistive material as previously defined.Alternately, each spline 52 may have a resistive coil wire wrappedaround it, as is previously described. A temperature sensor may also beattached to at least one spline for temperature controlled energydelivery.

In one embodiment, one long expandable section makes up the resistiveelement set 52. To support the length during treatment, a balloon isplaced inside the spline set. For example, this balloon may use aninternal lumen of the catheter (not shown) for inflation and deflation.Alternatively, as described for the braid device, the balloon may be aseparate device inserted into the long expandable spline set.

As discussed earlier with respect to the fixed diameter resistiveelement, spline resistive elements, when individually wired for power,may be used in conjunction with a multiplexing process. Such anembodiment allows for the sequential or “cascading” heating of specificresistive element subsets of the spline set. This may involve energizingat least one spline for a specific dwell time and then cascading ormoving to the next adjacent spline(s) until the end spline is reached.The cycle is then repeated until the complete treatment time is reached.

Super Elastic Expanding Ribbon:

FIGS. 12A-12C illustrate a catheter with a helical coil resistiveelement 55. For example, the coil resistive element 55 may bemanipulated from a collapsed or small diameter coil tightly wrappedaround the circumference of the catheter shaft (FIG. 12A) into anexpanded, large diameter coil (FIG. 12C). In one embodiment, this coilis made of a resistive type of material as discussed earlier. Theexpanded coil may also be in apposition with the vein wall. In oneembodiment, the catheter shaft is made of two concentric tubes, 56 and57. The proximal shaft 56 may be slightly larger in diameter to fit overthe distal tube 57. The distal tube is able to rotate about the cathetertube axis relative to the proximal tube. In the illustrated embodiment,clockwise rotation expands the resistive element (as shown in FIG. 12B)and counter clockwise rotation collapses the resistive element (as shownin FIG. 12C).

FIG. 12A shows the initial collapsed position of the device, which is,for example, how the catheter may be initially placed in the hollowanatomical structure. FIG. 12B shows mid-range of the radial expandingresistive element and FIG. 12C shows final state of the devicecompletely expanded. The coil is adjusted to eliminate the inter coilspacing by being pushed distally. The steps described are reversed inorder to collapse the device for new placement or for removal.

In one embodiment, for tube 57 to rotate and move axially, it isconnected to a torquable stylet wire (not shown). This stylet runsinternal to the catheter shaft and is accessible at the catheter handle.In one embodiment, the handle also allows these movements and locks thestylet in position in order to hold the resistive element collapsed orexpanded.

In another embodiment, the resistive element 55 is made of NITINOL®.Using the shape memory property when heated, the resistive element 55returns to its pre-shaped expanded coil form upon heating. In thisembodiment, one end of the coil 55 is tethered to the catheter, such asfor example, the proximal end. The expanded coil may also “autocollapse” as the hollow anatomical structure shrinks and/or constrictsduring the treatment. In another embodiment, a sheath is used toretrieve the coil after treatment.

FIG. 13A and FIG. 13B show another embodiment of an expandable flatstrip resistive element. These are radially expanding coiled strips 60.As shown, the device has at least one strip resistive element 60. FIG.13A shows the resistive element collapsed (i.e., coiled tightly). Byrotating the stylet component 59 in the clockwise direction as shown,the resistive element 60 winds up into a collapsed coil. In the samemanner, by rotating the stylet wire in the counter-clockwise direction,the coil 60 expands and adjusts to be in apposition with the wall of ahollow anatomical structure. The secondary stylet 58 is shown as astationary component (e.g., not rotatable). In other embodiments, stylet58 may also comprise a catheter tubing or component that attaches to theend of the resistive element.

FIG. 13B is an example of a 4-resistive element strip version of FIG.13A and is laid out flat. In this embodiment, the resistive elementstrips are resistive material as previously discussed. Components 58 and59 in this embodiment each contain at least one wire, which connects tothe resistive element strips. These strips then become heated whenenergized. Alternatively, the strips may have resistive wire wrappedaround them for coil type resistive elements

As previously described, one or more temperature sensors may be attachedto at least one strip for temperature-controlled energy delivery. Inaddition, these strip resistive elements may be used in conjunction withthe multiplexing process to heat specific subsets of the group ofresistive elements.

In an alternative embodiment, a resistive heating device can beconfigured such that the resistive heating element also acts as aresistance temperature device (RTD). Certain metals exhibit predictablyvarying electrical resistance properties at varying temperatures. Ifthis relationship is known for a given resistive heating element, atemperature of the element can be determined by measuring an electricalresistance across it. Such a system may advantageously eliminate theneed for additional thermocouples or other temperature sensing devices,or it may provide an independent sensing of temperature as may be usedfor high-temperature limitation.

In some embodiments, it is desirable to provide a heating elementconfigured to treat a relatively short length of an HAS at a singletime. Such an embodiment can be progressively moved through the HAS in aseries of discrete steps from a first position to a final position inorder to treat a desired length of an HAS. The process of moving aheating element through an HAS in a series of discrete steps betweentreatment steps is referred to herein as “indexing.”

The general process can proceed by providing an elongate catheter with ashort-length heating element at a distal portion thereof. The heatingelement and catheter can be inserted through an introducer sheath into ahollow anatomical structure such as a vein. The heating element is thenadvanced to a distal-most position, and power is applied. The heatingelement is allowed to ramp up to a desired temperature, and remains inplace for a desired dwell time. Once the desired dwell time is reached,the element can be powered down, and the element can be indexedproximally to a second position, at which point at least one of the rampup, dwell, power down, and indexing procedures can be repeated.

FIGS. 14 through 18 illustrate embodiments of short-length heatingelements and indexing systems. It should also be noted that the devicesdiscussed earlier are also applicable, but for this discussion the coilis used as the preferred embodiment. FIG. 14 illustrates one embodimentof an indexing HAS treatment system comprising an elongate catheter 70extending through an introducer sheath 71 which includes a hub 72, and aheating element 73 located at the distal end 74 of the catheter 70.

In some embodiments the heating element 73 is an electrically resistiveheating element such as those described elsewhere herein. For example,the heating element 73 can comprise a single, bifilar or otherelectrically resistive wire 75, as shown in FIG. 14A, wrapped in aloose, tight, or variable-pitch coil around a solid or hollow elongatestructure. In some embodiments, the heating element 73 has asubstantially short axial length. For example, in some embodiments theheating element 73 can be between about 1 and about 10 cm in length. Inone particular embodiment, a heating element 73 is provided with anaxial length of about 1 to 10 cm, as this range of length is believed tobe particularly advantageous for use with external compression appliedby hand, when the delivered heating energy less than about 100W andpreferably is in the range of 5-20W maximum, and when used incombination with an indexing system.

In order to accurately index the heating element by a desired amount, itis desirable to provide a means for repeatedly moving the heatingelement proximally by a desired distance. In some cases, this desireddistance is less than the overall length of the heating element in orderto effectively double-treat regions that may receive less heat energy asa result of an uneven heating profile along the axial length of aheating element. It may also be desirable to double treat a portion ofan initial and/or final treatment region in order to arrange for theindexing distances to correspond with catheter shaft markings or toarrange that after the full series of indexed treatments the finaltreatment region is in alignment with the end of the introducer sheath.In addition, it is desirable to have a means for preventing the heatingelement from being powered up while it is within the introducer sheath.Some examples of embodiments achieving these goals will now be describedwith reference to FIGS. 14 through 18.

In some embodiments, as illustrated for example in FIG. 15, the elongatecatheter 80 can comprise a plurality of markings along its axial lengthin order to assist in visual verification of indexing positions. Forexample, in some embodiments such as FIG. 16, the markings 81 comprisealternate colored or cross-hatched sections, each section having anaxial length approximately equal to the axial length of the heatingelement 82, less any intended overlap distance between treatments. Inalternative embodiments, as shown in FIGS. 17 and 18, the markingscomprise regularly-spaced lines or tick-marks at intervals correspondingto the indexing locations. In some embodiments it may be desirable toprovide a unique marker to indicate a final proximal-most indexedposition so that the heating element remains spaced from the introducersheath by a sufficient distance to prevent the sheath from melting.

FIGS. 19 through 35 illustrate embodiments comprising a catheter shaftwith a plurality of marks for manually or visually identifyingrespective indexing positions. For example, the marks can be spaced atone-centimeter intervals. For example the major increments of about 5centimeters can have numbers which increase proximally along the shaft.In use, the catheter can be indexed by moving it a known distancedetermined by reading the centimeter markings. In some embodiments, theinitial two treatments may overlap by as much as nearly the full lengthof the heating element, which is acceptable. Increments may be infractional dimensions, such as about 6.5 cm.

Each of the embodiments in FIGS. 19 and 20 comprises a movable datumdevice for establishing a starting position for a first treatment. ForFIG. 19, prior to a first heating treatment, the datum device 90 isadjusted to point at the nearest catheter shaft mark 91. This gives thephysician a starting point so that a fixed-length or measured-lengthindex step can be performed by aligning the catheter markings with thedatum pointer 90. Without an adjustable datum pointer 90, trackingfractions of centimeters can be confusing especially when other eventsare occurring.

FIG. 20 illustrates an embodiment comprising an axially adjustablesleeve 100 provided adjacent to the proximal end of the catheter andmountable to the introducer sheath hub 102. The adjustable sleeveprovides an adjustable datum 103 or starting point from which eachsuccessive indexing position can be measured in order to prevent thefinal position from entering the sheath.

FIG. 19 illustrates one embodiment which uses an introducer hub 92 as anattachment point for joining a datum device 93. The sleeve or body 93has a slot 94 which runs in the axial direction of the sleeve or body 93and ends near each before each edge so that it is an enclosed slot. Apointer device 90 is slidably positioned within the slot 94. The pointer90 is preferably mounted within the slot such that there is substantialresistance to sliding, so that it can maintain its position as areference. The sleeve or body 93 is clear or cut-away so the index marks91 on the catheter 95 can be seen as they approach the datum pointer 90.

An alternative embodiment comprising a slideable datum pointer isillustrated in FIG. 20. In this embodiment, the tubular sleeve 100attaches directly to the introducer sheath hub 102 and telescopesaxially along the longitudinal axis of the sheath hub 102. The sleeve100 can attach to the hub with threads or an interference fit so that itwill maintain its location relative to the hub 102 during use. Theproximal end 103 of the sleeve 100 of this embodiment acts as the datumpointer. The sleeve 100 is preferably clear so that each catheter mark101 can be seen as it approaches the datum mark 103. The datum mark 103may also be a colored line along the edge of the sleeve.

FIG. 21 illustrates an embodiment of an indexing system including acatheter with a heating element 110 at its distal end. According to thisembodiment, the distal section of the catheter shaft 111 located justproximal of the heating element 110 comprises a unique marking 112 toindicate the “stop treatment zone.” In some embodiments, the uniquestop-treatment marker 112 comprises a band of a solid or patterned colorsuch as red, yellow or other color or pattern that contrasts with thebase color or pattern of the catheter shaft. The stop treatment marker112 preferably has a length that is substantially equal to the length ofthe introducer sheath. In practice, introducer sheaths are provided inseveral known lengths (e.g., 5, 7 and 11 cm introducer sheaths arecommonly used). Thus, in some embodiments, it may be desirable toprovide several distinct stop-treatment markers corresponding to thevarious lengths of introducer sheaths. FIG. 21 also shows a similarslideable datum indicator as previously mentioned in FIG. 20. In thisversion, the datum mark 103 is on an accordion like sleeve 116.

In use, if the stop-treatment marker 112 is pulled proximally out of theproximal end of the sheath, the user will know that the heating elementis positioned within the introducer sheath. The user can then push thecatheter distally until the stop-treatment marker is hidden within thehub of the introducer sheath.

In alternative embodiments, with reference to FIG. 22A, additionalmarkers can be provided on the catheter shaft 120 proximally of thestop-treatment markers 112 as shown in FIG. 21. The markers of thisembodiment are generally configured to simplify the indexing process byremoving the need for counting individual centimeter-spaced markers. Theadditional markers 121 and 122 can comprise alternating colored segmentsor alternating dark/light segments. For example the marks can alternatefrom blue to white as in FIG. 22B. The alternating markers can alsoinclude symbols, numbers, letters such as “A” and “B,” as shown in FIG.22A, or other marks in order to further distinguish the indexingpositions. The lengths of the alternating segments are preferablysubstantially equal to the distance of the index steps. In someembodiments, the index steps are approximately equal in length to thelength of the heating element.

Alternatively, the stop-treatment markers on the catheter shaft can bearranged such that the index step marks are actually shorter than alength of a heating element. This encourages intentional overlapping ofindexed treatments. For example, for a heating element length of about 7cm, the shaft markers can be arranged to indicate a 6.5 cm index step.This can create a substantially consistent ½ cm treatment overlap.

In use, the catheter of this embodiment is placed within an HAS at adesired treatment position for an initial treatment. When treatment isabout to start the physician notes which catheter shaft color segment isadjacent to the introducer sheath hub. If the initial shaft markersegment is a first color (e.g. blue in the above example) then the indexstep for the second treatment is at the start of next blue mark on thecatheter shaft. Thus, the physician can pull the catheter proximally forthe full length of one white segment. If only a partial length of thevisible segment initially extends out of the hub, then the physician cansimply perform a partial-length index step after the initial treatment,as it is not believed to be detrimental to double-treat a short sectionof the HAS. Alternatively, the alternating shaft markers 113 and 114 asshown in FIG. 21 can have a length equal to half of the index length inorder to reduce the length of a double-treated section, thereby speedingthe overall process. Alternatively, one of the adjustable datumembodiments (FIGS. 19 and 20) above can be used to create a new datumpoint such that the second treatment is a full index distance from theinitial treatment. Alternatively a double treatment can be performed atthe beginning and/or at the end of the treatment procedure (i.e. duringthe final treatment increment).

Another embodiment, illustrated in FIGS. 23A and 23B, comprises printedmarkers arranged in a repeatable pattern for ease of indexing. Forexample as mentioned above the major 5 cm marks 130 and 131 can haveprinted numbers increasing proximally along the main body shaft 132.Between these major marks 130 and 131 there can be centimeter marks 133using a repeated group of the numbers such as 1, 2, 3 and 4 or letterssuch as A, B, C and D. Additionally, the shaft can have a pair ofmovable position-indicating sleeves, preferably clear, one of which isshown as 134. As shown in FIG. 23B, the proximal-mostposition-indicating sleeve 134 can be placed against the introducer hub135 marking the initial shaft marker-number for indexing. If for somereason the procedure was interrupted such that the physician forgotwhere he started and what the index datum was, the position-indicatingsleeve 134 can provide this information. The sleeve may indicate this asit is able to stay in place due to the friction fit even when thecatheter is temporarily removed from the introducer sheath. When it isreplaced or the physician comes back to continue treatment the sleevewill still be in place. The sleeve in place against the introducer hubwill imply that the next treatment step is the next identical proximalmarker-number 136.

In an alternative embodiment, illustrated for example in FIG. 24, asecondary sheath 140 may be provided and held in place by a compressibleo-ring type seal 141 (e.g. a Touhy Borst adapter) located at theproximal end of the secondary sheath 142. In its initial position, thedevice 143 has the secondary sheath 142 moved forward so that the distalend 145 is up against the distal therapeutic section 144, which isconfigured to limit travel of the secondary sheath, such as beingstepped in an increased diameter or by providing a physical stop at thedistal end such as a ring attached to the proximal end of thetherapeutic section 144. In one embodiment, the secondary sheath 142 isshorter in length than the main body by one index section.

Just prior to the initial treatment, as shown in FIG. 24D the secondarysheath 142 is adjusted until the change in color segments 146 becomesapparent. In an embodiment, this means the o-ring 141 on the secondarysheath 142 is loosened and then moved proximally while the main bodycatheter 143 and the introducer sheath 147 remain stationary. Once thesecondary sheath 142 is at the index step color transition, the o-ring141 is tightened. This gives the physician a starting point so that afull index step can be easily done. An untreated section can occur atthe end of the HAS adjacent to the introducer tip 148.

FIG. 25A illustrates an embodiment of an indexing system configured tofacilitate the regular positioning of the heating element during eachindexing step by providing automatic verification of a catheter positionwithin the HAS without requiring manual visual or tactile verificationof the catheter position by the physician. For example, a plurality ofmechanically or electrically detectable markers can be used to indicateto a physician that an indexing position has been reached. For example,a plurality of printed magnetic ink marks can be provided on thecatheter shaft 150. A magnetic reading sensor 151 can be placed adjacentto the introducer hub, and joined to a controller configured to producean audible or visible alert when each magnetic marker passes underneaththe sensor. This system allows for the index distance to be tracked andindicated to the physician visually and or audibly on the generatorwithout requiring the physician to visually watch markings on thecatheter.

In an alternative embodiment, FIG. 25B shows a device that uses a set ofdetents 143 along the catheter main body shaft. The locator 144,figuratively shown in FIG. 25B, fits over the catheter main body shaft.The locator may also attach to the introducer hub in order to hold itstationary. As the catheter is moved proximally, the follower 145, whichmay comprise a spring loaded cam, may click into a detent when it slidunder the tip of it. This would provide an audible and tactileresistance indicating proper index placement. The follower 145 may be aswitch connected to the system controller. This switch may tell thesystem the catheter has been indexed to the next position. The systemcontroller may also alert the physician that the catheter is ready fortreatment by audible and visual indicators.

In an alternative embodiment, illustrated for example in FIG. 26, atemperature sensor 151 (such as a thermocouple an RTD (resistivetemperature device) or a set of contacts that measure resistance) may beplaced on the shaft 150 of the catheter at a position proximal to theheating element 152 by a distance equal to the length of the introducersheath 153. Accordingly, a control system 154 may be located within thepower source or otherwise in electronic communication with the sensor.The control system 154 may monitor the temperature of the sensor 151during treatment. When the sensor 151 notes a significant drop intemperature relative to the patient's body temperature (e.g. a drop toroom temperature) caused by the sensor 151 leaving the HAS and enteringthe introducer sheath 153, the system alerts the physician that thetreatment is complete. Such an alert may be in the form of a visiblelight, and audible sound or another alert signal.

In the embodiment of FIG. 27, the catheter distal section 74 comprisestwo temperature sensors 160 and 161 on the catheter 74. A first sensor160 is positioned at or near the distal end 162 of the heating element163, and the second sensor 161 is positioned at or near the proximal end164 of the heating element 163. In embodiments in which the heatingelement 163 is an electrically resistive coil, “near the end” can meanthat the temperature sensor 160 or 161 is positioned in the coil winds,such as about one-quarter to about one-half of a centimeter from the endof the coil. In certain embodiments, the temperature sensors 160 and 161are preferably joined to a control system 165 configured to determinethe temperature at each point and to compare these values with oneanother.

In use, the catheter 74 of FIG. 27 may be placed in an HAS at a desiredinitial treatment site, which can be located using any availabletechnique. Energy can then be applied to the HAS in an initial treatmentstep. After the initial treatment, the device is moved proximally,during which time the control system 165 monitors the temperaturessensed by the two sensors 160 and 161. The section of the HAS treated inthe initial step will be at a higher temperature than the surroundingportions of the HAS. A significant drop in the temperature of theproximal sensor 161 relative to the temperature of the distal sensor 160implies that the heating element has been moved proximally out of thepreviously-heated region. Similarly, a significant drop in temperature(i.e., back toward body temperature) detected by the distal temperaturesensor 160 indicates that the coil has been indexed to the next adjacenttreatment position. The power source can be manually activated orprogrammed to automatically engage power once the heating element 160reaches its next indexed position.

By placing the temperature sensors in the coil, the indexed treatmentsmay create an overlap of adjacent treatment sections. In alternativeembodiments, the temperature sensors may be positioned at or closer tothe proximal 164 and distal 162 extents of the heating element 163 inorder to eliminate or reduce the amount of overlap in adjacent indexingpositions.

FIGS. 28 and 29 illustrate embodiments of indexing systems configured tofacilitate regular indexing movements of the catheter without requiringthe physician to be part of the control system. Also, for example,certain embodiments may facilitate automatic movement of the catheterfrom one position to the next indexed position without requiringverification of the position by the physician.

Another alternative embodiment, illustrated for example in FIGS. 29A and29B, uses a pair of o-ring type donuts 170 movably positioned on thecatheter shaft 174 and joined to one another by a string 171 or a rigidsliding rod 172. A first of these o-rings 170 may be attached to theintroducer hub 172, while the second 173 is permitted to move axiallyalong the length of the catheter 174, yet with sufficient friction thatit may also be used to grip and move the catheter 174 axially.

The system of this embodiment generally operates by movement of theo-rings after a treated section has been completed. In certainembodiments, before moving the catheter, both o-rings 170 and 173 shouldbe placed against the introducer hub 172 by sliding them on the cathetershaft. Next the more proximal o-ring 173 and the catheter shaft aremoved in tandem proximally away from the distal O-ring and introducerhub (also in tandem) until its motion is arrested by the string or rod171 or 172. This places the therapeutic element in a new adjacentsection for treatment.

In certain embodiments, the o-ring adjacent the introducer hub can beheld against the introducer sheath hub manually. Alternatively, thefirst o-ring may be configured to have an interference fit or mechanicalluer lock fit in order to attach to the introducer sheath hub.

If the o-rings 178 and 179 shown in FIG. 27C are to be joined to oneanother by a rod 172, the rod is preferably configured to limit theaxial travel of the first o-ring 178 with respect to the second o-ring179. In this embodiment, the o-rings 178 and 179 may have a tabextending radially outwards with a hole 180 therethrough. The rod 172may fit through the two holes 180 of both modified o-rings 178 and 179.This rod 172 may have stops 181 on both ends. In one embodiment, the rodends can resemble flat head nails.

Alternatively, the O-rings 170 and 173 can be shaped like a turkey wishbone. The side legs may fit around the catheter shaft in such a way thatit can be easier to slide axially along the shaft than come off of it.An appropriate elastic type of material such as silicone, KRATON®,urethane, or the like can be used so that the component can be pushedonto the shaft and have an interference fit in order to help anchor thecomponent in place until it is manually moved. As previously mentioned,the single short tab of the wishbone can be the extended tab with thehole 178 in it. The string or the sliding stop can use these holes asmentioned above.

Once the catheter is in position so that the heating element is at aninitial treatment site, both markers 170 and 173, shown in FIG. 29B, areplaced against the introducer sheath hub 172, and the initial treatmentis performed. The catheter 174 is then indexed, and a second treatmentis performed. After the initial and subsequent treatments, the catheteris indexed back or away from the initial treatment site. The distanceindexed is determined or limited by the length of the string or slidingstop. By having the o-ring 170, which is adjacent to the introducer hub172, remain there during the movement of the catheter 174, the secondo-ring 173 moves with the catheter until it is stopped by the string 171or sliding arm 172. This limit is visually apparent. Once indexed, theunanchored o-ring 173 is repositioned back adjacent to the stationaryo-ring at the introducer hub.

FIGS. 30 through 32 illustrate embodiments employing various linkages toindex the catheter by a desired amount. FIG. 30 illustrates a devicecomprising a linkage with two hinged arms 190 and 191. The linkage arms190 and 191 are of substantially equal length and hinged together. Incertain embodiments, the range of movement of the linkage arms is about0 to about 180 degrees. The range may be based upon the limit of traveldue to the cylinders 192 and 193 coming together (0 degrees) and whenthe linkage arm ends are tandem (e.g., the inverted “V” is spread open(180 degrees)).

This illustrated linkage 191 is connected to an anchor component 192which attaches to the introducer hub 172. The linkage 191 to anchorconnection may also comprise a hinge. A grip component 193 is attachedto the opposite end 194 of the linkage 190. This grip 193 is attached bya hinge connection 194 and is used to maneuver the catheter shaft 174.The linkage 195 may also have a spring or elastic component furtherlinking the two arms 190 and 191 and can keep the device in a preferredposition when not in use. Such a preferred position involves the gripcomponent 193 being located adjacent to the anchor 192 and introducerhub 172.

In one embodiment, the grip 193 is a component which straddles thecatheter shaft 174, and may be, for example, cylindrical. In oneembodiment, the grip 193 is not a complete circle and comprises an opensection configured to receive the catheter therein without the need forthreading the catheter through the center of the grip 193. In certainembodiments, the hinged end 194 of the linkage arm 190 is attached to anextended set of tabs 195 at one end of the grip 193. The physician caneffectively pinch the grip tabs 195 with the thumb and forefinger, whichin turn captures the catheter shaft. The inner radial surface of thegrip 193 can be, for example, a soft tacky type of silicone or KRATON.

FIG. 31A illustrates another embodiment of a mechanism that is similarto the previous linkage arm 195. In this embodiment, there are two setsof arms 200 and 201, making the device substantially symmetrical. Theanchor component 202, which attaches to the introducer hub 172 may beessentially the same as the embodiment of FIG. 30 except that bothlinkage arms 203 and 204 of this embodiment may be attached to it,and/or these connections can be hinged as well. At least one of thelinkage arms 200 and 201 may also have a spring or elastic component tokeep the device in a preferred position when not in use. This preferredposition is to have the grip component 205 adjacent to the anchor 202and introducer hub 172.

As previously mentioned, the two linkage arms sets are each made of tworods of substantially equal length, such that all four arms are equal.Each pair is hinged together. The range of movement is preferably about0 to about 180 degrees, although the device can be limited to narrowerranges as desired.

The grip component 205 may be attached by a hinge for each of the twoarms. An alternative embodiment may include a complete cylindricalcomponent that is threaded over the catheter shaft. As shown in FIG.31B, by use of at least one o-ring inside the grip 205, the double armlinkage can grip the shaft as it was indexed and release as themechanism returned to the adjacent position next to the introducer hub.The o-ring inside the grip 205 may have an interference fit on thecatheter shaft 172. When the grip is moved away from the introducer hub,the o-ring may come against a tapered surface 206, which can cause theo-ring to tighten its fit on the catheter shaft. The tapered surface maybe of an angle to accommodate two o-rings 207 of different sizes forimproved gripping forces.

For ease of use of this mechanism, in certain embodiments, the apex ofboth linkage arms may have an additional component 208 that the thumband finger can push against to make the device work.

FIG. 32A illustrates another embodiment of an indexing device comprisinga mechanical indexing handle 220. This illustrated embodiment of theindexing handle 220 may be threaded over the main catheter body 172 andtreated as an accessory. The indexing handle front end 223 may beconfigured to securely attach to the hub 172 end of an introducersheath. The introducer sheath can become the stationary basis to indexthe catheter 172 during treatment of the HAS. This indexing handle 220can be designed to step the main body of the catheter 172 proximally aset distance relative to the introducer hub.

In the embodiment of FIG. 32A, the accessory handle engages the cathetermain body for indexing. In certain embodiments, the catheter cable isconnected to the generator in the standard fashion and is separate fromthe indexing handle. The handle may have a set trigger travel or a setindex distance. As the handle is triggered, the mechanism grasps thecatheter main body and moves it proximal relative to the handle, whichis stationary. At the end of the travel, the handle mechanism thenreleases the catheter main body and returns to its initial position. Incertain embodiments, this mechanism us similar to the o-rings shown isFIG. 31B. Alternatively, the mechanism may be a cam action componentwhich is pushed against the main body tube as it starts its pull backand then is released at the end of the travel or index distance.

An alternative embodiment of the index handle is illustrated in FIG.32B, and comprises two cables and is substantially integral to thecatheter main body 172. In certain embodiments, the cable 222 extendsfrom the proximal end of the catheter main body to the indexing handle224. The handle 224 may have one or two switches, such as an OFF buttonand an ON button to remotely control the power from the generator duringtreatment as required. Alternatively this may be a toggle switch tocombine the two modes. Alternatively, this may be a momentary switchwhich signals the generator to power up or power down. The handle mayhave the second cable 221 extending from it and can be designed toconnect to the generator.

FIGS. 33 through 34 show several alternative embodiments using a remoteswitch integral to the handle or as a separate remote switch. FIG. 33Ashows the buttons 230 integral to the catheter handle 231 and the cable221 attached to the generator 154. FIG. 33B illustrates an alternativeembodiment with the remote switches 232 separate from the catheterhandle 231. In certain embodiments, the remote cable and the cable tothe generator join within the catheter handle 231.

FIG. 34A illustrates yet another embodiment showing the remote switcheson a separate cable 240 to the generator 154. The illustrated cathetercable 221 and catheter are separate from the remote. FIG. 34Billustrates a similar embodiment and shows a footswitch and cable 250 inplace of the remote cable 240.

FIG. 35 illustrates an embodiment of an indexing system that relies oninformation input to a control system. In certain embodiments, thesoftware of the control system determines the length and number of indexsteps based on the information from the user. The relevant informationmay include the length of the inserted portion of the catheter afterfinal placement and the overall length of the introducer sheath from tipto the back end of the hub. The software determines the index step sothe treatments can overlap for the total treatment of the saphenous veinstarting at the SFJ and ending near the introducer sheath tip. FIG. 35illustrates an embodiment of the information screen of the controlsystem. The items 260 through 266 point out information which may bedisplayed during treatment. Item 260 indicates the elapsed time from thestart of the treatment. The actual elapsed time for the specific indextreatment 261, the temperature of the current treatment 262, the indexstep in progress of the full treatment 263, the number of index segmentscompleted 264, the index segment currently being treated 265, and thepower being used for the current index segment treatment are also shown.In certain embodiments, items 263 and 265 are determined by thecontroller using the physician input of the catheter inserted length andthe introducer sheath length. FIG. 36 illustrates a general flowchart ofthe control system from the physicians' point of view and indicates thesteps as they pertain to the treatment, according to one embodiment ofthe invention.

Methods of using an indexing HAS treatment system will now be described.The methods described herein can employ any suitable device describedabove or otherwise known to the skilled artisan. For example, in oneembodiment, an indexing method can comprise inserting a heating elementwith a length of about 5 to about 7 cm into a distal-most section of anHAS to be treated. Power can then be applied to the heating element fora desired length of time to treat the segment of the HAS adjacent to theheating element. After a desired dwell time, the power supply to theheating element can be reduced or shut off. With the power off (orsubstantially reduced), the heating element may be indexed proximally(i.e., the heating element can be moved proximally until the distal endof the heating element is adjacent to the proximal end of the segment ofthe HAS that was just treated).

An example of an index treatment includes treatment at a temperaturebetween approximately 95° C. and approximately 110° C. for a dwell timeof approximately 20 seconds or less. In a more preferred embodiment, thepreferred index treatment is performed at approximately 95° C. for adwell time of approximately 20 seconds. The ramp time to temperature maybe approximately 10 seconds or less, with a preferred time ofapproximately 5 seconds or less. The intent is to reach and maintain thetreatment temperature quickly in order to apply heat to the HAS in alocal manner. Once a section is treated, the distal therapeutic portionof the catheter is moved to the adjacent section. In certainembodiments, the catheter has an overlap portion of approximately 1 cmor less to substantially reduce or eliminate the number of under-treatedsections or gaps as mentioned earlier. This process is repeated untilthe treatment of the HAS is complete. Temperatures like 110° C. at ashorter dwell time are also possible, but the depth of treatment varies.

Except as further described herein, any of the catheters disclosedherein may, in some embodiments, be similar to any of the cathetersdescribed in U.S. Pat. No. 6,401,719, issued Jun. 11, 2002, titledMETHOD OF LIGATING HOLLOW ANATOMICAL STRUCTURES; or in U.S. Pat. No.6,179,832, issued Jan. 30, 2001, titled EXPANDABLE CATHETER HAVING TWOSETS OF ELECTRODES; or in U.S. patent application Ser. No. 11/222,069,filed Sep. 8, 2005, titled METHODS AND APPARATUS FOR TREATMENT OF HOLLOWANATOMICAL STRUCTURES. In addition, any of the catheters disclosedherein may, in certain embodiments, be employed in practicing any of themethods disclosed in the above-mentioned U.S. Pat. No. 6,401,719 or6,179,832, or the above-mentioned U.S. patent application Ser. No.11/222,069 filed Sep. 8, 2005. The entirety of each of these patents andapplication is hereby incorporated by reference herein and made a partof this specification.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the inventions. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the inventions.

1. (canceled)
 2. An apparatus for treatment of a hollow anatomical structure (HAS), the apparatus comprising: a catheter sized for insertion into the HAS, the catheter including an elongate shaft having a proximal end, a distal end, and a working length adjacent the distal end; and a plurality of energy application devices positioned sequentially along a longitudinal axis of the catheter along the working length; wherein the energy application devices are configured to be energized sequentially, such that each energy application device is energized for a preset dwell time, and after the dwell time has elapsed a next one of the energy application devices is energized for the preset dwell time.
 3. The apparatus of claim 2, wherein the dwell time is approximately 0.2 seconds.
 4. The apparatus of claim 3, wherein each of the energy application devices is energized for a total of approximately 0.6 seconds during each cycle.
 5. The apparatus of claim 2, wherein three of the energy application devices are energized at a time.
 6. The apparatus of claim 5, wherein during a first treatment cycle a first one, a second one, and a third one of the energy application devices are energized, and during a second treatment cycle the second one, the third one, and a fourth one of the energy application devices are energized.
 7. The apparatus of claim 6, wherein during a third treatment cycle the third one, the fourth one, and a fifth one of the energy application devices are energized.
 8. The apparatus of claim 2, wherein the energy application devices comprise electrically resistive coils.
 9. The apparatus of claim 8, further comprising at least one insulative outer sleeve encasing the resistive coils so as to prevent electrical contact and electrical conduction with tissue.
 10. The apparatus of claim 2, further comprising at least one temperature sensor.
 11. The apparatus of claim 10, further comprising a plurality of temperature sensors, each of the temperature sensors corresponding to one of the energy application devices, such that each of the energy application devices is individually temperature controlled.
 12. The apparatus of claim 2, wherein the sequential energy application devices may be used in a power control mode that relies on manual energy control.
 13. The apparatus of claim 2, further comprising a temperature sensor associated with a distal-most one of the energy application devices, wherein the distal-most one of the energy application devices is used for an initial treatment, and successive ones of the energy application devices use a same energy-time profile as the distal-most one of the energy application devices.
 14. The apparatus of claim 2, wherein energizing each of the energy application devices comprises multiplexing through each of the energy application devices.
 15. The apparatus of claim 2, wherein the dwell time spans a duration from a start of a treatment of an adjacent portion of the HAS until a completion of the treatment of the adjacent portion of the HAS.
 16. A method for treating a hollow anatomical structure (HAS), the method comprising: inserting a catheter into the HAS, the catheter including an elongate shaft having a proximal end, a distal end, and a working length adjacent the distal end; and a plurality of energy application devices positioned sequentially along a longitudinal axis of the catheter along the working length; advancing the catheter through the HAS until the working length is located at a treatment site; and applying energy sequentially to the energy application devices, such that each energy application device is energized for a preset dwell time, and after the dwell time has elapsed a next one of the energy application devices is energized for the preset dwell time, thereby heating and constricting a lumen of the HAS at the treatment site.
 17. The method of claim 16, wherein the dwell time is approximately 0.2 seconds.
 18. The method of claim 17, wherein each of the energy application devices is energized for a total of approximately 0.6 seconds during each cycle.
 19. The method of claim 16, wherein three of the energy application devices are energized at a time.
 20. The method of claim 19, wherein during a first treatment cycle a first one, a second one, and a third one of the energy application devices are energized, and during a second treatment cycle the second one, the third one, and a fourth one of the energy application devices are energized.
 21. The method of claim 20, wherein during a third treatment cycle the third one, the fourth one, and a fifth one of the energy application devices are energized.
 22. The method of claim 16, wherein the energy application devices comprise electrically resistive coils.
 23. The method of claim 22, wherein the energy application devices further comprise at least one insulative outer sleeve encasing the resistive coils so as to prevent electrical contact and electrical conduction with tissue.
 24. The method of claim 16, wherein the energy application devices further comprise at least one temperature sensor.
 25. The method of claim 24, wherein the energy application devices further comprise a plurality of temperature sensors, each of the temperature sensors corresponding to one of the energy application devices, such that each of the energy application devices is individually temperature controlled.
 26. The method of claim 16, further comprising using the sequential energy application devices in a power control mode that relies on manual energy control.
 27. The method of claim 16, further comprising a temperature sensor associated with a distal-most one of the energy application devices, wherein the distal-most one of the energy application devices is used for an initial treatment, and successive ones of the energy application devices use a same energy-time profile as the distal-most one of the energy application devices.
 28. The method of claim 16, wherein energizing each of the energy application devices comprises multiplexing through each of the energy application devices.
 29. The method of claim 16, wherein the dwell time spans a duration from a start of a treatment of an adjacent portion of the HAS until a completion of the treatment of the adjacent portion of the HAS. 